Search results for "Reflection"
showing 10 items of 645 documents
Bloch analysis of finite periodic microring chains
2005
We apply Bloch analysis to the study of finite periodic cascading of microring resonators. Diagonalization of the standard transfer matrix approach not only allows to find an exact analytic expression for transmission and reflection, but also to derive a closed form solution for the field in every point of the structure. To give more physical insight we analyze the main features of the transmission resonances in a finite chain and we give some hints for their experimental verification
Unrestricted Shapes of Jellium Clusters
1995
A jellium model with a completely relaxable background charge density is used to study metal clusters containing 2 to 22 electrons. The resulting shapes of the clusters exhibit breaking of axial and inversion symmetries, as well as molecular formation. The clusters without inversion symmetry are soft against deformation. The strongly deformed 14-electron cluster is found to be semi-magic. Stable-shape isomers are predicted.
Improving the vertical radiation pattern issued from multiple nano-groove scattering centers acting as an antenna for future integrated optics Fourie…
2019
The stationary wave integrated Fourier transform spectrometer (SWIFTS) is based on the sampling of a stationary wave using nano-scattering centers on the surface of a channel waveguide. Single nano-scale scattering centers above the waveguide surface will radiate the sampled signal with wide angular distribution, which is not compatible with the buried detection area of infrared (IR) detectors, resulting in crosstalk between pixels. An implementation of multiple diffraction nano-grooves (antenna) for each sampling center is proposed as an alternative solution to improve directivity towards the detector pixel by narrowing the scattering angle of the extracted light. Its efficiency is demonst…
INTRODUCING THE SIRIPRO PROJECT: THE SICILY GEODYNAMIC SETTING. STATE OF THE ART
2009
Reflection high energy electron diffraction as a tool in cluster deposition experiments
2010
Reflection high energy electron diffraction (RHEED) is used to study the structure and orientation of mass-filtered iron clusters upon deposition ontoW(110). The present setup enables in situ investigations during deposition and thermal annealing. Particles as small as 2 nm at low density on the surface can be studied. The experiments reveal that larger particles with a diameter of about 13 nm are randomly oriented on the substrate with a preferred tendency to rest on their surface facets. Thermal annealing leads to a partial realignment and a significant flattening of the particles. In contrast 2 nm particles are found to align spontaneously in an epitaxial manner on W(110). Thermodynamic …
Structural modulations and phase transitions in β-eucryptite: an in-situ TEM study
1999
Beta-eucryptite as grown by the flux method has been investigated by in-situ cold- and hot-stage transmission electron microscopy (TEM). Using electron diffraction and dark-field TEM imaging, we found no evidence for the merohedral twinning that accompanies structural collapse at the β-to-α-quartz transition, suggesting a true hexagonal symmetry for the aluminosilicate framework of β-eucryptite. Selected-area electron diffraction (SAED) patterns exhibited a variety of incommensurate structures along the three a axes with an average modulation period of about 6.5 a. These modulated structures arise from superperiodic stacking parallel to (100) of two structural units with different Li config…
Autobiographical texts written by learners of Catalan as an Additional Language: From formative needs to reflection in the teaching of narrative genr…
2022
In this article we analyse autobiographical narrative texts written by university students studying Catalan as an Additional Language at a CEFR (2020) B1 level. The goal is to analyse the formative needs related to the writing of this genre in order to foster metadiscursive reflection in the classroom that will allow students to improve their written output. To this end, we analyzed a corpus of 39 autobiographies at both the macrotextual level (i.e., rhetorical moves) and the microtextual level (i.e., deictic elements which channel the narrative’s organization). Our results show that the problems that these texts present for students are related to awareness of the elements that define the …
Etched LPFGs in reflective configuration for sensitivity and attenuation band depth increase
2016
A reflection configuration setup for long-period fiber gratings is presented. It permits to obtain a unique band with attenuation double than that obtained in transmission configuration, which is interesting for applications where this value is reduced (e.g., the mode transition phenomenon). The method is based on the deposition of a silver mirror at the end of the optical fiber, which permits to absorb the power transmitted through cladding modes and to avoid the generation of interferometric bands. The method also solves the requirement of a precise cleave or to polish the end of the grating, a drawback present in other publications. The versatility of the setup has been proved by applica…
Student Mentoring in the Master Programme “Pedagogy”: the case of University of Latvia
2019
There is a developing interest in mentoring and tutoring in the higher education in Latvia. Mentoring is looked at as a retention strategy to support students to remain and continue studies and as a tool to prevent students’ drop out from the university. Since academic year 2016/2017 several programmes of tutoring and mentoring in basic studies (bachelor level studies)have been developed and financially supported at the University of Latvia, but so far mentoring has not been used for Master level students. The Master program “Pedagogy” includes a theoretical course “Methods of Mentoring at the Educational Institution”. Since academic year 2018/2019 new tasks were introduced for the second y…
Una política juvenil para promover el desarrollo local: un estudio de caso
2019
El artículo presenta un estudio de caso de una política juvenil realizada en la última década en una región del Sur de Italia. Su interés reside en la versatilidad, el enfoque multidimensional y en el hecho de haber actuado como un óptimo instrumento de desarrollo local. El estudio de caso se ha realizado a través del análisis documental de las evaluaciones ex -ante, durante y ex – post que se hicieron para valorar el impacto de la política. La reflexión que el caso propone se enfoca en cómo se puede promover eficazmente el desarrollo local a través de políticas más trasversales.